Chronic inflammatory diseases of the oral cavity are often aggravated during pregnancy. In addition, there are marked changes in skeletal metabolism during pregnancy and lactation, yet the status of dental mineralized tissues is not well known. It is possible that changes in dental soft and hard tissues that may occur during pregnancy and lactation may predispose some individuals to some of the more serious aspects of periodontal disease. Alveolar bone remodeling during pregnancy and lactation will be determined. Fluorescent bone markers are given at intervals and the remodeling activity is determined by histomorphometric methods. Quantitative image analysis of microradiographs will determine changes in bone structure and mass. The presence and extent of gingival inflammation and/or edema will be quantified at the light and electron microscope levels. The extent to which the maternal hard and soft tissues are restored to 'normal' after weaning of the pups will be evaluated in a similar manner. Skeletal calcium may be used to supply calcium for fetal skeletal mineralization during pregnancy and milk production during lactation. The extent of skeletal calcium mobilization may depend on the availability of dietary calcium. The relationship and importance of dietary caclium to alveolar bone remodeling and bone mass during pregnancy, lactation and recovery after weaning will be determined. In addition, the relationship of overall calcium metabolism to changes in dental mineralized tissue remodeling during the reproductive cycle will be established. The general calcium metabolic parameters to be measured include dietary intake, intestinal absorption capacity, fecal and urinary excretion, placenta and mammary gland transfer and whole bone calcium. These studies will determine the changes that occur in dental soft and hard tissues during pregnancy, lactation and recovery after weaning. The importance of dietary calcium intake on mineralized tissue remodeling during the reproductive cycle will also be established.